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Why does penicillin not treat tuberculosis?
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Penicillin is ineffective against tuberculosis because the tubercle bacillus (Mycobacterium tuberculosis) is naturally resistant to it.1
While penicillin functions by inhibiting the bacterial enzymes responsible for cell wall synthesis in replicating microorganisms, it does not successfully target the specific biological structure of the tuberculosis pathogen. Consequently, the treatment of tuberculosis requires specialized antituberculosis antibiotics, such as isoniazid, rifampin, ethambutol, and pyrazinamide, which are specifically formulated to disrupt the unique physiological processes or cell wall components of the tubercle bacillus.234